Quantitative sulfur poisoning of nanocrystal PtO₂/KL-NY and its deactivation mechanism for benzene catalytic oxidation

The present study involved the synthesis of a kaolin-based NaY zeolite (KL-NY) supported nanocrystal PtO₂ (5–10 nm) catalyst, which exhibited complete benzene conversion at 195 °C. However, a certain amount of sulfur species led to severe deactivation of the catalyst. This deactivation was mainly caused by the reduction of active lattice oxygen. XPS, H₂-TPR and HRTEM results confirmed that adsorbed sulfur species competitively consumed active lattice oxygen, resulting in a transition of partial PtO₂ to PtO. Generated PtO cannot actively participate in the oxidation reaction due to its weaker oxidation property, indicating a decrease of active species induced by sulfur poisoning. Furthermore, Al₂O₃ outside the KL-NY framework can adsorb sulfur species and form Al₂(SO₄)₃, leading to an increase in acid sites. Due to the weak acid-tolerance of KL-NY, partial porous structure destruction occurred with a decrease in specific surface area and pore volume, thereby negatively impacting catalyst performance. © 2024 Elsevier Ltd